As the tortured, can’t-catch-a-break strummer, Isaac is on screen in nearly every scene of the movie, offers plenty of subtlety and showcased some impressive singing chops to boot. He smiled quietly at the question, though, and offered only that he had to find a different way into the real-life Ronk. “I’m not a six-foot-four Swede,” deadpanned the actor, who appeared at least five inches shorter, and not Scandinavian.

So where has the 33-year-old come from? Born in Guatemala, educated at Juilliard and a nearly 10-year verteran of the U.S. screen, Isaac has in recent years had supporting parts in big-budget pictures “Robin Hood” and smaller indie titles such as “W.E.” He’s been known only to niche fans. But that will change with “Davis,” which in a couple of Cannes screenings has already established him as an early acting contender when the awards hoopla gets underway later this year.

Maybe it’s the sight of him as an irascible-but-endearing drifter, or just the hair and beard, but watching Isaac in the film felt a little like watching Mark Ruffalo in “You Can Count On Me” for the first time.

Isaac acknowledged there were some challenges in making the movie. He struggled, for instance, in locating the right tone for the numbers, which are all sung live, “Les Miserables”-style. The breakthrough moment came at the home of legendary record producer T-Bone Burnett, who oversaw the film’s music. “He said 'Sing It to me like you sing it to yourself,'” Isaac noted.

Davis is one of the more complicated musician characters to grace the screen in a while, and not in the hard-living, “Behind The Music” sort of way. He has the musical chops, but also a peculiar form of integrity—his enemies would call it abrasiveness--that keeps success at bay. Because of this, the character needs to be both complicated and inherently likable, a rare hybrid, something Isaac balances deftly. As Ethan Coen said, “We were screwed until we met Oscar.”

There was still plenty of heavy lifting, though. Isaac said that, given the movie’s tone, he and the Coens had to work a lot on creating the world of early 60’s New York folk. “A lot of it was so underplayed and so quiet that [the world] needed to be constructed in a full context,” he said.

There’s a certain parallel between Isaac and his character, particularly in the roundabout road to success. Awards pundits will no doubt make some hay of this season. With a kind of easygoing affability, Isaac seems to show none of the same disdain for those around him. But the actor says he thinks the singer has a sympathetic side, too. “[Llewyn's failures] are probably a combination of bad timing and some self-destructive tendencies,” Isaac said. “But those tendencies were coming from a place of authenticity.”